With the development of the UMTS (Universal Mobile Telecommunication System) third-generation (3G) mobile communication system, a user will be able to have at his or her disposal one or more than one mobile terminals (portable telephone, PDA: Portable Digital Assistant, pocket videophone or micro-computer). This will allow high-speed communication for the exchange of voice and image data while in motion and telecommuting situations. The need for data and video services (database, file transfer, high resolution facsimile, mobile video telephony) and the interconnection with broadband networks require an increasing amount of processing and a large quantity of energy.
Thus, in case of mobile telephones, the download time of a video image or audio file in the multimedia applications MPEG4/H.263 and MP3 and the display of the video images involve a great consumption of energy, which, as a result, reduces talking time. Moreover, the batteries now obtainable in the market do not supply enough power, considering the increase in calculation required by multimedia applications.